Healing After Endodontic Microsurgery Using a Rotary Bur Versus Piezoelectric Unit for Osteotomy and Root Resection

The goal of this clinical trial is to compare bone healing after using apical tooth microsurgery to remove root end infection, either by use of rotary burs for cutting bone and root end, or by use of piezoelectric surgery for the same procedures. The main questions it aims to answer are: * Is there a difference in bone healing and reformation between the two surgical procedures ? * Is there a difference in bone healing between cutting the bone with a rotary bur and cutting the bone with the 'bone window' technique that uses piezoelectric unit ?

Inclusion Criteria: * Age 18 years and older consenting to the surgical procedure as well as agreeing to preoperative, postoperative and at least one follow-up CBCT evaluation after 12 months * Noncontributory medical history (American Society of Anesthesiologists class I and II) * A history of previous endodontic treatment with radiographic presence of apical periodontitis * A true endodontic lesion: microsurgical classification A, B, or C according to Kim and Kratchman, 2006. * Lesion size 10 mm or smaller in diameter measured on preoperative CBCT * Coronal restoration should be present at the time of follow up examination. Exclusion Criteria: * Nonconsenting patients and patients younger than 18 years of age * Medical history with American Society of Anesthesiologists class III to V * Insufficient coronal restoration * Nonrestorability or traumatized teeth * Teeth with microsurgical classification D, E, or F according to Kim and Kratchman, 2006. * Mobility I or higher * Radiographic presence of nonapical root resorption * Teeth with a vertical root fracture or coronal/ midroot perforation * Lesion size larger than 10 mm in diameter measured on preoperative CBCT * Use of bone graft material for regeneration